Several other double jacketed fire hoses are presently on the market. One of the traditional constructions of a double jacketed fire hose includes: extruding a polyurethane liner or tube; applying a heat activated adhesive to the outer surface of the tube or liner; inserting the tube or liner with the adhesive applied thereto into a woven jacket; inflating the inner tube or liner with steam to cure the adhesive and attach the liner or tube to the jacket, and, finally, inserting the inner jacket into the outer jacket. This method produces a double jacketed hose which has some unfavorable characteristics. Specifically, this method produces hoses whose liners or tubes become loose resulting in useless hoses. The inner liners or tubes detach from the jacket when the adhesive deteriorates.
Additionally, some of the adhesives used in the aforestated process must be used very quickly after the application of the adhesive to the inner jacket, or liner or tube. This makes the manufacturing process very cumbersome.
Another process developed in this industry is covered by a United States Patent issued to Joncker, et al., U.S. Pat. No. 4,738,735. The Joncker, et al. patent is directed to a method for continuously extruding an elastomeric material on the interior of a continuous tubular woven fabric in a loom. In this process the liner is applied as a hot melt coating at the weaving point in the loom. The extruder or coater is mounted directly over the loom and as the jacket is woven the extruder or coater leaves or applies a layer of hot melted urethane directly on the interior of the inner jacket created by the weaving.
The inner jacket created by the Joncker process is then inserted into an outer jacket. This double jacketed hose wherein the inner jacket has been coated by the Joncker process has performed unsatisfactorily. There are several reasons why hoses produced using the Joncker process are unsatisfactory. First, the inner jacket produced by the Joncker process is not untwisted. Second, the inner jacket produced by the Joncker process does not fit snugly within the outer jacket. Third, the inner jacket produced by the Joncker process is not sized so as to fit precisely within the inner diameter of the outer jacket. Fourth and finally, the fibers of the inner jacket produced by the Joncker process continue to stretch after repeated high-low pressure fluctuations in service causing the bunching up of the inner jacket inside the outer jacket.
The double jacketed hoses produced by either the traditional method and/or the Joncker process bunch up and/or kink. Put another way, they do not perform as one unified hose or assembly rendering the hoses relatively inefficient over time. Specifically, it is well known in the art that a natural twist exists by virtue of the manufacturing process and equipment which produce woven jackets. This natural twist will be described in greater detail hereinbelow. The traditional method employing an extruded tube or liner is insufficient in that the adhesive deteriorates permitting separation of the liner from the woven jacket. Another reason for the separation of the tube from the woven jacket is the aforestated twist which exists in the woven jacket.
The double jacketed hoses produced employing the Joncker process to manufacture the inner jacket are unsatisfactory because the twist imparted to the inner jacket produced by said process is not controlled or removed from the inner jacket when it is inserted into the outer jacket. These hoses, when pressurized, severely twist. The inner jacket produced by the Joncker process rotates within the outer jacket which, under certain conditions, can completely obstruct the flow of water. Additionally, hoses having large amounts of twist result in loose fittings and/or disconnections. Fittings are used where two hoses are joined together at a union or where a hose is connected to a fire plug. Additionally, in the situation where the hose is being held or supported by a fireman he can be subjected to injury.